1. Field of the Invention
The present invention relates to a wireless data transport method, and a mobile terminal and an interworking function device therefor, and more particularly, to a wireless data transport method in which a direct connection through a circuit-switched data (CSD) channel to a server is possible, and a mobile terminal and an interworking function device therefor.
2. Description of the Related Art
Data transferred through a data communication channel are divided into circuit-switched data (CSD) and packet-switched data (PSD). A channel for the CSD is exclusively occupied by a user connected, but a channel for the PSD is shared by many users in packet units. However, existing networks being in use adopt a CSD channel mode in general and network service providers prefer the CSD channel due to the problem of charge collecting.
FIG. 1 shows conventional main protocol layers of a transport system 1 adopting a circuit-switched data (CSD) channel. Referring to FIG. 1, in a connection method of the conventional transport system, assuming that an identifier to be connected, e.g., a telephone number, is XXXX, a mobile terminal 2 requests a connection to a specific host of an interworking function (IWF) device 3 using an ATention Dial (ATD) command including the identifier, i.e., ATD XXXX. Then, a modem 6 of the IWF device 3 calls a pre-specified host 5 through a public switched telephone network (PSTN) using the telephone number. As a result, a call configuration between the host 5 and the IWF device 3 is achieved. Accordingly, a transport session is established between the mobile terminal 2 which asks for a service and a host, such that the information service to the mobile terminal starts.
However, such conventional connection method through the CSD channel utilizes a land line modem 6 that is installed in the IWF device 3, which is connected to a PSTN through the modem 6, and the connection to the HOST or external packet network is achieved through this PSTN. The method has a disadvantage in that a delay factor exists since it performs a modem connection in a state in which a CDMA CSD air connection is already set. Further, the method has a disadvantage in that the air connection may be disconnected due to timing out in the PSTN, so that a call may be interrupted unintentionally.
As described above, in a case where a wireless terminal adopting WAP (Wireless Application Protocol) utilizes the application with a network interface such as a web service, as illustrated by the direct connections of WAP 8 and 9 in the mobile terminal 2 to the respective corresponding WAP 10 and 11 in the host 5, a method for a direct connection to the network interface using a CSD channel, and not a modem, is required.
To solve the above problems, it is an object of the present invention to provide a wireless data transport method in which, when a mobile terminal intends to use the application with a network interface such as a web service, the wireless terminal can be connected directly to the network interface which is the Internet connect port, using a circuit-switched data (CSD) channel, and not using a modem.
It is another object of the present invention to provide a mobile terminal capable of being directly connected to the network interface through the CSD channel when performing the application for connection with the Internet, which is embodied by the above method.
It is still another object of the present invention to provide an interworking function (IWF) device for connecting directly the mobile terminal to the network interface through the CSD channel.
Accordingly, to achieve the above first object, there is provided a wireless data transport method comprising the steps of performing a dialing in the mobile terminal using a predetermined command with an identifier including an IP (Internet Protocol) address. RLP (Radio Link Protocol) between the mobile terminal and the IWF device is synchronized to establish a circuit-switched data (CSD) channel according to the command, and then PPP (Point-to-Point Protocol)/TCP (Transmission Control Protocol) is performed in the IWF device according to the identifier. Then, a network interface channel is opened by an AT (ATtention) processing unit of the IWF device according to the IP address of the identifier.
According to an aspect of the second object, there is provided a mobile terminal comprising: an AT (ATtention dial command) processing unit for performing a dialing using a predetermined command with an identifier including an IP (Internet Protocol) address; a data formatting unit for formatting the data output from the AT processing unit into a circuit-switched data (CSD) format; and an RLP (Radio Link Protocol) performing unit for performing RLP synchronization for a radio link between the mobile terminal and the IWF unit to establish a CSD channel.
According to another aspect of the second object, there is provided a mobile terminal comprising: an AT (ATtention dial command) processing unit for performing a dialing using the ATtention Dial (ATD) command with an identifier including an IP (Internet Protocol) address; a data formatting unit for formatting the data input from the AT processing unit into a circuit-switched data (CSD) or a packet-switched data (PSD) according to the selection of a user; and a radio link protocol performing unit for performing an RLP synchronization for a radio link between the mobile terminal and the IWF unit to establish the channel selected according to the command.
According to an aspect of the third object, there is provided an interworking function (IWF) device comprising: an RLP (Radio Link Protocol) performing unit for performing synchronization with the mobile terminal for a radio link, to establish a wireless data channel; a data formatting unit for extracting dialing information from data of the circuit-switched data (CSD) format input through the RLP performing unit; an ATtention Dial (ATD) processing unit for extracting an identifier including an IP (Internet Protocol) address from the dialing information; and a network interface unit to connect to a network server corresponding to the identifier.
According to another aspect of the third object, there is provided an interworking function (IWF) device comprising: an RLP (Radio Link Protocol) performing unit for performing synchronization with the mobile terminal for a radio link, to establish a wireless data channel; a data formatting unit for selectively extracting an identifier by identifying whether the data input through the wireless data channel connected by the RLP performing unit has a circuit-switched data (CSD) format or a packet-switched data (PSD) format; an ATention Dial (ATD) processing unit for performing dialing using a predetermined command with the identifier if the extracted identifier is a telephone number; a modem unit to connect to a server corresponding to the telephone number via a public switched telephone network (PSTN) if the extracted identifier is a telephone number; and a network interface unit to connect to a server corresponding to IP (Internet Protocol) address if the extracted identifier is an IP address.